1 [C] something that is not or must not be known by other people 秘密；机密: to keep a secret 保守秘密to let sb in on/tell sb a secret 向别人泄露秘密I can't tell you where we're going -- it's a secret. 我不能告诉你我们要去哪里─这是秘密。 It's no secret that they don't like each other (= everybody knows). 他们都不喜欢对方，这已不是什么秘密。

2 [sing] the secret (of/to sth/doing sth) the only way or the best way of doing or achieving sth 秘诀；窍门: What is the secret of your success (= how did you become so successful)? 你成功的秘诀是什么？